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Initial acoustical measurements
were performed in The Orpheum in 1994. The most serious
problem was the image shift heard on the balcony. Image
shift is an acoustical phenomenon where the sound appears
to be coming from a location other than true source. For
listeners on the balcony, singers or soloists appeared to
be perched somewhere above the ceiling. Underneath the
balcony overhang, the acoustics were dry and lacked
loudness. |
| Vancouver's much loved Orpheum Theatre
is the home of the Vancouver Symphony. It was saved from
the wrecker's ball in the 1970s, brought up to date and
given a permanent orchestra shell. It remained however
more of a vaudeville house than a concert hall - at least
in terms of acoustics. A long-term renovation project has
been initiated by the Vancouver Civic Theatres to address
these problems and others like it in The Orpheum, Queen
Elizabeth and Playhouse Theatres. Financing for the
project is generated through parking and seat surcharges,
thus allowing the upgrade of these civic buildings
without burden to the taxpayer. Construction has been
carried out in the summer months when the theatres are
dark. |
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The renovated acoustics of The
Orpheum have been very well received by music makers and
concertgoers alike. The image shift on the balcony has
been eradicated and the listeners underneath the balcony
now experience some of the best acoustics in the house
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Synopsis of the Work
Acoustical
measurements to quantify existing conditions
User Surveys & Feasibility Study
Listening Tests using binaural convolution of data
Computer Modeling
Small Scale Modeling
Listening Test of proposed fix (binaural convolution)
HVAC Noise Control
Electro-acoustic fix underneath the balcony
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The project marked the first
complete application of small scale
acoustical modeling in North America and the
first time that a Canadian municipality has
hired a Canadian acoustician to direct the
design of a major concert hall.
Until recently, acoustical
scale modeling was limited to scales no
smaller than 1:10. Recent research has
allowed us to significantly reduce the size
of our models, down to 1:50.
For The Orpheum this would
have meant a model as big as a bedroom,
hermetically sealed and dried to less than 2%
relative humidity. Such a model would have
cost over $300,000 to build, nearly half of
the entire construction budget for the
acoustical fix. The model we used for The
Orpheum was about the size of an office desk
and cost only $10,000 to build.
Scale modeling is a useful
research tool and has been employed by
Aercoustics on a 1:50 model of a prototype
co-generation plant Heat Recovery Steam
Generation (HRSG) building. Other work
conducted by Aercoustics since completing The
Orpheum includes a 1:25 model of the new
University of Regina Theatre and a 1:50 model of an Omnimax cinema, recently on display at the Ontario
Science Centre. Anticipated uses of small
scale modeling, other than auditorium design
include industrial facilities and
environmental noise propagation studies.
The director of Vancouver
Civic Theatres said: "We have what I
will boastfully term an unqualified success.
The results have exceeded our
expectations." The application of
modern engineering solutions in The Orpheum,
particularly in the form of small scale
modeling, demonstrate a confidence in
acoustical design unheard of twenty-five
years ago.
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Vancouver Symphony Web Site: http://www.vancouversymphony.ca
Vancouver Civic Theatres Web Site: http://www..city.vancouver.bc.ca |
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